1. Field of the Invention
This invention relates generally to the field of parking control and enforcement, and more specifically in particular embodiments to parking meters, enforcement, agents, dispatching systems, and the communications mechanism that link them.
2. Description of the Related Art
Parking meters have long been used to generate revenue and control the sharing of a limited resource. Devices to detect coins have use infrared radiation, the Hall effect sensors, light sensors, and magnetic fields. Some of these methods are described in U.S. Pat. No. 4,460,080 (Howard); U.S. Pat. No. 4,483,431 (Pratt); U.S. Pat. No. 4,249,648 (Meyer); U.S. Pat. No. 5,097,934 (Quinlan); U.S. Pat. No. 5,119,916 (Carmen et al). As time has passed, systems have been developed which include the use of microprocessors, ultrasonic transceivers and IR transceivers for the purposes of detecting the presence of a vehicles and communicating information to outside devices. The power requirements of these systems has led to the use of solar cells to recharge batteries. Solar power cells however, have the drawback of not being useful in areas of limited sunlight or in other conditions which block or retard sunlight, such as snow and rain. As parking meters have become more complex, the need to send and receive information to parking enforcement personnel has increased. The limited range and ease of blocking IR transceivers has led to the use of RF transceivers to transfer data as disclosed in U.S. Pat. No. 4,356,903 (Lemelson et al.); U.S. Pat. No. 5,103,957 (Ng et al.); U.S. Pat. No. 5,153,586 (Fuller); U.S. Pat. No. 5,266,947 (Fujiwara et al.); U.S. Pat. No. 5,777,951 (Mitschele et al.).
Parking meters in general generate revenue in two different ways. The first way that parking meters generate revenue is through the collection of coins at the parking meter device itself. The second method of generating revenues is by means of ticketing vehicles and collecting the corresponding fines for the tickets. In general, the process of ticketing involves much inefficiency. The traditional method of ticketing vehicles is to have an enforcement person drive through the area containing the meters and then visually observe the meters and whether a vehicle is parked in the metered space. There is no easy way for a traditional meter enforcement person to know which area contains the most violations in order to efficiently ticket the vehicles. In addition, some parking areas require that a vehicle vacate the parking space at the end of a predetermined period. The enforcement of such regulation involves the marking of the vehicle, such as by placing a chalk mark on the tires of the vehicle. An enforcement person then returns to the vehicle within a predetermined period to observe if the vehicle has not moved by observing the orientation of the mark on the tires. In addition, parking regulations may change with the time of day. For example, an area which allows a vehicle to park on Saturday and Sunday may not allow a vehicle to park between the hours of 7:00 to 9:00 a.m. and 3:00 to 6:00 p.m., to clear the area for rush hour traffic. Currently, the only way to enforce such restrictions is to have a meter enforcement person drive past the area and visually observe the vehicles parked during the forbidden times. There is currently no easy way for a parking enforcement person to know a priori that there are vehicles illegally parked in one area without actually going to that area. There is also no way to know how many vehicles are illegally parked in an area. The result is that the enforcement of parking regulations and meter regulations has proven to be a hit and miss, random affair. Because parking enforcement vehicles can not be routed directly to areas containing violators and must depend on chance and visual observation, the enforcement of parking regulations is not as efficient as it might be otherwise. In order to enforce parking regulations, more vehicles are needed than would otherwise be needed if the areas where violations were transpiring were known.
To overcome limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification discloses an electronic parking meter system. The parking meter portion of the system comprises electronic circuitry within a parking meter housing which may replace or supplement the traditional housing and contains sensors that provide information about the state of the meter that is whether it is registering a violation, time expired, or is currently metering time. In addition the parking meter electronic circuitry may register information such as the state of the power supply that powers the circuitry, the presence or absence of a vehicle in a space being metered, and whether or not the meter has been tampered with. The electronic circuitry contains controller circuitry, typically a low power microprocessor that periodically awakens and checks the state of all of the sensors. If any one of the sensors has changed state since the last time the microprocessor awoke (i.e. performed non standby processing functions), the microprocessor can power a radio transmitter and transmit the new state of the system. The transmission of state information typically comprises the transmission of a number of parking meter data packets containing state information. The packets are transmitted to a concentrator unit over a predetermined maximum time period using an appropriate transmission schedule such as one generated from a suitable chaotic map. If there is no state change when the microprocessor system awakes it simply goes back to sleep. The radio within the parking meter need not contain a receiver, only a transmitter. The system broadcasts data packets only when state changes occur in order to help comply with FCC part 15 requirements.
The filtering and collecting of the data packets from meters can be achieved typically by a concentrator system housed within a weather proof box mounted high up on a utility pole or other suitable object. The concentrator system is typically placed within radio range of all of the parking meters whose transmissions it is to receive. The concentrator system typically contains two microprocessors that are linked directly together. The first microprocessor is coupled to a radio receiver that listens for data packets from the parking meter radios, filters out duplicate packets and send a single packet, representing a state change in a meter system, on to the second microprocessor. The second microprocessor stores the packets from the first microprocessor in memory while waiting for a data request from a data collection system, or an appropriate time to transmit the information to the data collection system. The second microprocessor typically is connected to a spread spectrum radio transceiver (with greater range than the parking meter radios) and is in constant communication with the data collection system. The spread spectrum radio can be located within the same box as the concentrator system.
The data collection system typically comprises a computer system that is linked to a spread spectrum radio receiver, for communicating with a plurality of concentrator units. Typically a spread spectrum link provides the data link to the various filtering and collecting concentrators and to various enforcement vehicle systems, such as meter maids, towing services, repair services and the like. The data collection system software typically stores the data collected from the parking meters, issues dispatch messages to the enforcement systems, and responds to messages from the enforcement systems that indicate what action was taken with respect to the dispatch messages. Using the information collected from the concentrators, the current state of any parking meter can be conveniently examined.
The software within the data collection system also typically provides a mechanism that allows the operator of the system to associate a calendar with each parking meter. For example the data collection system, by referring to the calendar, is able to check if streets are clear of parked vehicles for a variety of events such as: parades, street sweeping, street maintenance, etc. and is able to dispatch remedial measures.
A further aspect of the present invention is an enforcement system. The enforcement system can be portable and is typically intended to reside aboard an enforcement vehicle. It is typically connected to a spread spectrum radio that provides it with a constant communication link to the master data collection system. Software located in the enforcement system empowers the enforcement officer to select a violation site, notify the master data collection system of enforcement activity, indicate to the master data collection system what action was taken at the site, or to query the master data collection about violations at a particular site.
Other embodiments of a system in accordance with the principles of the invention may include additional aspects and alternate implementations. One such aspect of the present invention is that the parking meters may communicate their change of status using an easily implemented protocol without the complex scheduling and protocol which may be present in many Time Division Multiple Access (TDMA) and Time Sharing schemes.
Additionally the present invention provides a method of collection of useful data on the pattern of parking violations that would otherwise be difficult or costly to obtain. Such data may be used to cost effectively schedule enforcement, and thereby increase efficiency and revenue generation.
These and other advantages and novel features, which characterize the invention, are pointed out in the following specification. For additional understanding and clarification of the invention, its advantages and variations reference should be made to the accompanying drawings and descriptive matter, which illustrate and describe specific examples of embodiments of the invention.